Rubber impregnated metal cable and method of making same



Jan. l2, 1937. R. MAYNE RUBBER IMPREGNATED METAL CABLE AND METHOD OF MAKING SAME Filed July 5, 1954 nL/yz? ZFDEEZ" `.Z175 ne E WWW Patented dan.. l2, i937 oarrasl stares RUBBER llTi/JIPREGNTED T/ETL @i WTE AND ME'EHQIB @F ration oil New orlr Application italy El, lldf, Serial No tllt .lll maitres..

This invention relates to rubber impregnated metal Vcable and to methods o making the saine. The article of the invention is especially useful for transmission oi power or for hoisting purposes where great resistance to internal chaiing or abrasion due to dering of the cable is required.

This application is in part a continuation of my application Serial No. 651,276 filed January l2, i933.

w l-leretoiore it has been common to employ stranded wire cables for hoisting and power transmission purposes and for other uses where the cable is subjected to intermittent bending at high velocities. As flexing oi the cable and stretching of the elements thereof results in movement of the individual wires with relation to each other, it has been necessary in the past to apply oil or grease to the cables to prevent abrasion or chalng oi the wires upon each other.

Such lubricants have also served to protect the wires from corrosion.

The presence of grease and oil on the cables not only reduces their tractive power, but also makes them disagreeable to handle and they cannot be used where their contact with material in process of manufacture would soil the mate rial.

While it has been proposed to apply rubber coatings to the strands of ropes or cords made oi vegetable or metallic fibers, especially where the ropes or cords were to be incorporated in rubber and fabric structures, such as tires, the introduction of rubber between the wires of a metallic cable, alter the cable has been formed, and vul canization or the rubber to the wires has been accomplished, has heretofore been difficult of achievement, because of the methods by which such cables are manufactured.

As the Wires are comparatively stili, any attempt to apply an unvulcanized coating of rubber composition to the individual wires before they 1 are assembled Aresults either in scraping of the rubber from the wires duringv their passage through the cabling machine, or in the plastic rubber being forced from between the wires by the stresses in the wires which hold ,them in twisted relation.

Where itis attempted to coat the wires separately and to vulcanize .the coatings before the 5@ Wires are assembled in cable form, while it may be possible to handle the wires through the cau bling machine, the resulting vstructure permits motion between vthe coatings in use which soon destroys the coating.

The principal objects of the invention are to (CE. litten?) provide resilient cushioning of the wires, to elim inate internal abrasion, to eliminate lubrication, and to provide protection against corrosion.

A more specific object is to provide a cable in which the wires are spaced from each other and the space therebetween is 'filled with a resilient rubber composition which is bonded to the Wires so as to permit movement of the wires in the cable without abrasion of each other.

Other objects will appear from the following description and the accompanying drawing.

Of the drawing:

Fig. l is a perspective View of a dissected por tion of a simple form of cable.

Fig. 2 is a perspectlveview of a portion of one of the wires thereof showing the metallic coat:- ings thereon.

Fig. 3 is a cross-sectional view of a compound cable, showing the invention in. its preferred forni.

Referring to the drawing, and especially to Fig. l., the numeral l@ designates one of a group of helically disposed wires which are positioned about a core wire lila in spaced relation to forni a simple cable. The Wires lil are preferably of smaller diameter than the core wire la. so as to insure their being spaced apart circumferential ly.. Each wire is enclosed in a coating il of a rubber adherent metal. The interstices between the wires are entirely occupied by a 'resilient vulcanized rubber composition filling it? and an additional cover i3 of similar rubber material surrounds the other elements, the rubber composition being bonded by vulcanization to the metallic coating l l surrounding the wires.

The metallic coating ll preferably comprises a mixture of copper and zinc deposited electrically. ln order to prevent hydrogenation of the wire during the depositing of the coating i l, it is advisable to employ, in the making o the cable, wire which previously has been coatedwith tin or other metal not subject to hydrogenation. 'When the coating of tin or other metal is used ythis is designated by the numeral Ill.

In order to provide space between the wires l! and the core wire Illa throughout the greater portion of their extent the wires are preformed to the course of their disposition in the finished cable before the cable is assembled, as this minimizes the absenceV of voids between the wires due to static stresses in the wires resulting from the cabling thereof. For the'sarne reason the wires l@ are merely laid without substantial tension so that they are separated circumierentially from each other. This provides space for the rubber when the rubber is forced into the interstices of the cable. It will be understood that the equal spacing of the wires is an ideal condition and that in practice the core wire Ilia will contact at some places with the wire I0.

In the manufacture of a simple cable according to the invention, after the wires have been preformed to lie without strain along the desired helix, they are loosely cabled together.

Referring to Fig. 3, this illustrates a compound cable having greater flexibility than the simple cable of Fig. 1. In this form of the invention a number of helically preformed wires I5, preferably six are assembled around a straight central wire I6, of slightly larger diameter, toform a simple cable or strand. A plurality of similar strands, preferably six, are similarly formed of a straight central wire I1, somewhat smaller than wire i8, and a plurality, preferably six, of helically preformed wires I8, slightly `smaller than wire i1, to provide strands slightly smaller than the central strand. The outer strands are then helically preformed and laid about the central strand.

In the compound form of the invention the individual wires are preferably tinned before assembly to avoid hydrogenation. This coating and the overlying coating of rubber ,adherent metal have been omitted in Fig. 3 to avoid complicating the drawing.

The formed cable, whether of simple or compound construction, is cleaned to remove all grease, dirt and rust. This may be accomplished by use of detergent and pickling solutions in any well known manner. I prefer, however, first to dissolve all solid grease by washing the cable in solvent naptha, gasoline, or other organic solvent, then, by brushing the cable to remove all foreign matter.

Thereafter the cable may be further cleaned by successive applications of alkaline caustic material and pickling acid, such as sulfuric acid. These operations may be performed continuously by passing the cable progressively through the solutions and finally washing and reeling the cable.

In order to secure adhesion of the wires to the rubber thereafter to be applied. the coating of rubber adherent metal Il may now be applied by electroplating the assembled cable. In order to remove moisture remaining in the cable after the electro-plating operation, the cable is rst thoroughly dried., This may be accomplished by passing it through a delrvdrat'ing agent such as alcohol and then drying itin heated air.

In order thoroughly to fill the interstices between the wires, a coil of the cable is placed in a closed vessel adapted to be evacuated of air. Air is removed from the vessel by a pump. A thick rubber cement is then introduced into the vessel around the cable. After the coil of the cable is covered by the cement, the cement is subjected to super-atmospheric pressures until the interstices are completely filled with rubber. The cable is then removed and permitted to dry. As the cable is loosely laid and the wires are substantially free from static stresses, the wires normally lie apart throughout the greater part of their extent and a cushion iilling I2 of rubber is deposited between them. The rubber cement may be of any desired composition but is preferably of thev viscosity of a solution having four pounds of vulcanizable masticated rubber to one gallon of benzine.

After'the interstices of the cable have been filled, the cable is removed from the cement and permitted to dry. A coating i3 of vulcanizable rubber composition is then applied to the cable, preferably by passing the cable through the insu lating head of anextrusion machine. The rubber is then vulcanized to the metal by application of heat and pressure. A convenient manner of confining the cable during vulcanization is by means of a. lead sheath which may be applied around the cable by the extrusion process. Where this is done the ends of the vlea-:l sheath may be sealed and the sheathed cable immersed in. a bath of hot water or other liquid under such pressure as closely to compact the sheath around the cable by hydrostatic pressure, the plasticity of the lead being of assistance in permitting such compacting cf the sheath.

The resulting article has its wires Substantially separated and cushioned by the rubber filler which permits movement of wires with relation to each other without abrasion of the wires and without the necessity of lubrication.

While two forms of wire cable only have been shown it is to be understood that cables having a different number of wires and with the wires differently arranged are within the scope of the invention.

I claim:

1. The method of making a iiexible tension ele ment which comprises forming a metal cable, thereafter depositing a coating of rubber-adherent metal thereon, filling the interstices between the wires of the cable with a rubber composi tion, and vulcanizing the resulting structure.

2. The method of making a iiexible tension element which comprises forming a metal cable with a coating of rubber-adherent metal on the wires thereof, evacuating the interstices of the cable, filling the interstices with a rubber composition, and vulcanizing the resulting structure.

3. The method of making a flexible tension element which comprises completely filling the interstices between the wires of a metal cable with a rubber composition, applying a cover of rubber composition to the cable, temporarily enclosing the cable in a lead sheath, and vulcanizing the rubber.

4. The method of making a flexible tension element which comprises completely filling the interstices between the wires of a metal cable with a rubber composition, applying a cover of rubber composition to the cable, temporarily enclosing the cable in a lead sheath, and vulcanizing the rubber while compacting the sheath by fluid pressure.

5. The method of making a flexible tension elementI which comprises loosely cabling a plurality of preformed wires to form a cable, thereafter coating the wires with rubber adherent material, filling the interstices between the wires with a soft rubber composition, and vulcanizing the rubber.

6. The method of making'a flexible tension element which comprises loosely cabling a plurality of preformed wires to form a cable, thereafter coating the wires with rubber adherent metal, filling the interstices between the wires with a soft rubber composition, and vulcanizing the rubber.

7. The method of making a exible tension element which comprises loosely cabling a plurality of preformed wires to form a cable, thereafter coating the Wires with rubber adherent ma terial, filling the interstices 'between the wires with a soft rubber composition, applying a coat- E3. Wh

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